Do you have a visa?

>>1128397
No, does everyone need one? I have a british passport

>>1128429
There was a temporary visa exemption for UK citizens valid through... I think it's this month. Check your embassy website to see if it's still valid.

If not, visas on arrival can be procured, but you have to sign up for them in advance... Lots of online travel agents doing this with 24-48 hour turnaround. You get an approval letter that you hand in with your passport at the VOA window. Easy enough to do.

Assuming you either don't need or don't mind getting a visa, and that you've never been in Hanoi before, the old part of town around Hoan Kiem lake is an obvious first choice--lots of narrow streets, cafes, restaurants, and bars, nice atmosphere if a bit heavily touristed (the north end of the lake is sort of a backpacker ghetto, but locals eat and drink there too). Great atmospheric place to wander in for a few hours.

Also excellent is the relatively new National Ethnographic Museum. If you want some communism, the Ho Chi Minh mausoleum and museum are of also of some interest.

>>1128389
Oh, and regarding time, you should be OK. Give yourself about an hour of taxi transit time each way--you may not need that long but the traffic can be pretty insane. But assuming daytime hours you should have plenty of time for a meal and a look around.